Flow synthesis of N-alkyl-5-methyl-2-pyrrolidones over Ni₂P/SiO₂ catalyst

N-alkyl-5-methyl-2-pyrrolidones are an attractive alternative to the common solvent N-methyl-2-pyrrolidone (NMP) and can be used as starting materials for synthesis of various valuable chemicals. Reductive amination of alkyl levulinates derived from biomass feedstock is a promising method for production of these compounds. In the present work, N-alkyl-5-methyl-2-pyrrolidones were obtained in excellent yields by reductive amination of ethyl levulinate with alkylamines over SiO₂-supported nickel phosphide in a flow reactor using molecular hydrogen as a reducing agent. At the same time, aromatic amines and 1-nitropropane give a lower yield of the corresponding pyrrolidones. The influence of the solvent nature, temperature, pressure, hydrogen and liquid flow rates on the catalyst performance was studied.